1. Field of the Invention
The invention relates to a medical instrument with an endoscope to the preamble of claim 1.
2. Brief Description of the Prior Art
An electrosurgical instrument with the above noted features is already known, in which an angular intermediate member is provided between the fixed ring and an elongated hole in the second lever (German patent 26 28 555). Another instrument is known, in which several gripping arms are centrally displaceable in the endoscope shaft and there is also a follow-up of the periscope (European patent 117 894).
In the known instruments of this type, a wire loop carrier, e.g. comprises two parallel tubular rods, which are guided by means of a few guidance parts on the periscope and are interconnected and, at the patient-near end, carry the said wire loop (German utility model 19 41 759). On the working member there is generally provided a straight sliding link mechanism, through which the surgeon can operate the wire loop which is supplied with a radio-frequency current at the patient-near end. Such instruments are used for removing tissue in the urethra and the bladder.
In other constructions, use is made of an endoscopic periscope with a large field of view, which facilitates the operation. However, the endoscope shaft end is always visible in the field of view, which has a disturbing effect.
In addition, a probe is known for the removal of ureteroliths with a gripper arrangement positioned at the front end of a catheter tube and which can be opened and closed by means of an operating cable guided within said tube. On the front end of the catheter tube is arranged a longitudinally displaceable sleeve which carries a radially widenable, inflatable cuff. In addition, an image transmitting light guide is provided concentrically in a ball. In general terms, the image transmission through the flexible light guide is inferior to that with a rigid periscope. Moreover, such a probe cannot be used in certain medical cases, where a rigid endoscope is required (DE-OS 2 927 726).